1. Field of the Invention
The invention relates to photolithography on a substrate having more than one level.
2. Description of the Related Art
By way of background explanation, in photolithography techniques features are printed by passing light through a “reticle”, which acts as a mask and is typically formed from glass printed with chrome patterns. In order to print lines the reticle is provided with slits which allow the light to pass through onto the photoresist (a photosensitive layer used to coat silicon in photolithography techniques).